Smoke pollutant concentrator

ABSTRACT

An improved type of air pollution control device wherein microparticles of a size incapable of normally being picked up by a conventional electrostatic precipitator are agglomerated by the use of an unbalanced and intermittent electrostatic field which agglomerates them to sufficient size to facilitate removal. In addition to agglomerating particles the attracting electrodes are arranged in a uniquely spaced arrangement of zones so that a progressive cleaning action occurs during movement of the gaseous medium through the unit to thus, in effect, achieve self-cleaning without the need for shutdown which would otherwise be required.

United States Patent [191 Stone SMOKE POLLUTANT CONCENTRATOR [63]Continuation-impart of Ser. No. 731,906, May 24, 1968, abandoned, whichis a continuation-in-part of Ser. No. 501,678, Oct. 22, 1965, abandoned.

[52] U.S. Cl. ..55/ll0, 55/123, 55/128,

[51] Int.-Cl ..B03c 3/04 [58] Field of Search ..55/l01,l23,128,129,130,55/136, 137, 138, 139, I40, 143, 145, 146,

[56] References Cited UNITED STATES PATENTS 2,978,066 4/1961 Nodolf..55/155 X 51 Feb. 27, 1973 FOREIGN PATENTS 0R APPLICATIONS 699,67011/1953 Great Britain ..55/128 Primary Examiner-Dennis E. Talbert, Jr.Attorney-J. William Freeman et a1.

[57] ABSTRACT An improved type of air pollution control device whereinmicro-particles of a size incapable of normally being picked up by aconventional electrostatic 'precipitator are agglomerated by the use ofan unbalanced and intermittent electrostatic field which agglomeratesthem to sufficient size to facilitate removal. In addition toagglomerating particles the attracting electrodes are arranged in auniquely spaced arrangement of zones so that a progressive cleaningaction occurs during movement of the gaseous medium through the unit tothus, in effect, achieve selfcleaning without the need for shutdownwhich would otherwise be required.

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INVENTOR. CHARLES W.v STONE BY j/WM r ATTORNEY SMOKE POLLUTANT.CONCENTRATOR RELATED APPLICATION This application is acontinuation-in-part of applicants pending application, Ser. No. 731,906for Air Pollution Control Means filed May 24, 1968 now abandoned, whichapplication was a continuation-inpart of applicants still earlier filedapplication identified as Ser. No. 501,678 filed Oct. 22, 1965, nowabandoned. i

In the earlier filed application above referred to, Ap-

plicant disclosed the use of a grouping of a bare elec trode and anelectrode encased in a dielectric coating to create an unbalancedelectrostatic field so as to cause agglomeration on an encapsulatedelectrode. While this principle is used in each of the several stages ofthis application, the further improvement that exists herein is that thespacing is controlled and arranged in such a fashion that the advancingparticles are subject .to increasingly strong periodically interruptedor intermittently applied electrostatic fields so as to be drawnprogressively through the unit and ultimately discharged in an operationthat may be deemed selfcleaning.

BACKGROUND OF THE INVENTION This invention generally relates to airpollution control and involves an electrical device designed toconcentrate foreign material which may be carried in a gaseous mediumsuch as smoke.

PRIOR ART In addition to the above referred to copending application ofthe applicant, attention is also directed to Strubler U.S. Pat. Nos.3,110,580 and 3,257,779. The Strubler U.S. Pat. No. 3,110,580 usesalternately arranged electrodes that are inserted within dielectrictunnels so as to theoretically cause particle attraction to occur bygravity upon subjecting of the electrodes to the influence ofalternating current. The Strubler U.S. Pat. No. 3,257,779, whileembodying the same basic concept, sets forth a particularly shapedelectrode of a distinct stellate cross sectional profile.

In both Strubler patents the electrode was always arranged so as to beencircled by a dielectric material such as a ceramic wall. In thisfashion during the period that the electrode of Strubler was in anegative condition the particles would be repelled towards the ceramicwall surface while an attraction of such particles would exist in theelectrode during the period that the same was in positive condition. Inpractice, it has been found that the operation of the Strubler devicewas predicated upon an extremely sensitive humidity condition to avoidarcing.

SUMMARY OF THE INVENTION Applicant initially improved over the prior artby, in

effect, inserting the electrode within the dielectric wall portions ofStrubler and connecting the same to the alternating current systemsupplied. The net effect of this I arrangement was to create anencapsulated electrode that created an unbalanced condition in theelectrostatic field with the encapsulated electrode being incapable ofemitting a strong charge because of the dielectric component thatsurrounds the same.

As a result of this condition it follows that an electronic unbalancewas created that resulted in the electrons being attracted to thesurface of the dielectric material because of the inability of the sameto repel the electrons with equal force and effect. In this regard, ananalogy may be drawn between a normal wall surface and one covered witha sticky substance representing the surface of the encapsulatedelectrode while the regular wall surface would be analogous-to the bareelectrode employed in the applicants concept. Using ping pong balls asan example of electrons, it is obvious that there would be a differencein repelling force of the two surfaces and this is the situation thatapplicant has created in his first application so as to, in effect,create an unbalance.

Such an arrangement creates the ability of the unit to agglomerateparticles on the dielectric surface which greatly facilitates thecleaning of the unit with agglomeration being necessary in order tocreate particles of proper size that can be removed by conventionalcleaning filters.

While the above has constituted a marked advance over the prior art,applicant has further. discovered that the need for cleaning at all canbe eliminated by arranging the electrodes in a particular fashion.Specifically, each of the bare electrodes is preferably formed with aflared out frontal portion that serves as a funnel type of divertingdevice for particles being moved off of an upstream encapsulatedelectrode with the progressive distance between the outboard bareelectrodes being decreased so that ultimately the advancing agglomerantsmay be collected by a vacuum tube or other means at the end of the unitand automatically removed therefrom. Further, the electrostatic field ispreferably applied intermittently by pulsing or interrupting the currentsupply at a rate dependent upon the velocity of flow of the gaseousmedium through the device.

In this regard, while this principle has been found to be operable onunits using the same electric current to all of the electrodes, it isobvious that assistance in this regard could be given by progressivelyincreasing the intensity of electrostatic field so as to cause a greaterattraction to be encountered progressively through the unit in thedirection of flow with this assisting in the transfer of agglomerantsfrom one encapsulated electrode to the next aforesaid downstreamdielectrode.

Production of an improved air pollution control means having the abovecharacteristics accordingly becomes the principal object of thisinvention with other objects thereof becoming more apparent upon areading of the following brief specification, considered and interpretedin the light of the accompanying drawings.

Of the drawings:

FIG. 1 is a top view with a portion of the top enclosures broken away topermit greater facility in illustration.

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1.

FIG. 3 is a side plan view of the encapsulated or enrobed electrode ofthis invention.

FIG. 4 is a top plan view partially broken away and in section of amodified form of the invention.

FIG. 5 is a sectional view taken on the line 55 of FIG. 4.

Turning now to thedrawings and particularly to FIG. I, the smoke controlunit of this invention will be seen indicated generally by the numeral10. The unit 10 includes a casing 11 comprised of spaced side walls 12and 14, bottom wall 16 and top enclosure 18 defined by a metallic plate20 and a dielectric plate 22. If desired, and as shown, the longitudinalends of unit 10 may be left open allowing a free flow of the gaseousmedium through the now defined passageway 24. However, as will beunderstood, perforated or grated plates in shiftable relationship toeach other may be employed. Such a embodiment would permit some controlover the amount of gaseous medium introduced into the unit 10 which may,at times, be advantageous.

In the passageway 24 are spaced a plurality of electrodes. Asillustrated, these include bar electrodes 35, 37, 39, 41, 43 and 45 andencapsulated or enrobed electrodes 34, 36, 38, 40, 44, 46 and 48. Theenrobed electrodes, as best seen in FIG. 3, have their current carryingmaterial 50 imbedded in a dielectric or nonconductive substance 52, forpurposes which will become evident. The substance 52 should have theproperties of low porosity, high electrical rupture strength, andmoderate resistivity. The resistivity should be of an order of magnitudeallowing a small milliampere flow density over a given surface area. Forexample, at an applied voltage of 15,000 to 20,000 volts, a resistancepermitting a current flow of 1 to milliamperes per square inch has beenfound satisfactory. Dielectric substances 52 may include quartz, silicaglass, borosilicate glass such as Pyrex, the compound Vycor (Trademarkof Corning Glass Company) and other similar materials. Also to benoticed are the relationship somewhat in pairs or pollutant removalstations, between the bare electrodes and the enrobed electrodes as, forinstance, between electrodes 37 and 38 and between electrodes 43 and 44.The various pairs generally transversely arranged, as for examplestations 37-38 and 43-44, form pollutant removal zones.

When the unit is energized, in a manner which will hereinafter bedescribed, the whole of passageway 24 becomes an electrical field, butdue to the kind and arrangement of the electrodes employed, deliberateinequalitiesoccur in the electrical field with the electrical strengthbeing greater near the bare electrodes and less near the enrobedelectrodes. In effect, electrical currents are activated within theelectrical field of unit 10 since it is known that electricity willnaturally flow from a point of saturation to a point of deficiency.Consequently, in the unit 10, the deficiencies will occur in the area ofthe enrobed electrodes causing the direction of flow to be to theenrobed electrode from its transversely related bare electrode.

Therefore, the gaseous medium which is introduced into the unit 10 mustflow through an electrical field. As a result, many of the particles,minute or microscopic as they may be, in the composition of the gaseousmedium become ionized or charged. Having been so ionized, the particlesbecome subject to the aforementioned currents within the electricalfield of the unit 10. As a result, the particles will be directed to andgather on, near, or adjacent to each of the several enrobed electrodesas the gaseous medium passes through the unit 10, thereby assuringreentry of the gaseous medium into the atmosphere in a much cleanercondition.

Further, it will be seen that the relationship between the bare andenrobed electrodes is not limited only to transverse direction butexists also in the longitudinal direction. For instance, as seen in FIG.1, electrode 37 is paired with electrode 38 in transverse direction buthas an extending, bent portion or flange 37a cooperating with theoutside edge 36a of the electrode 36 in the longitudinal direction.

It has been observed that it is desirable for the particles gatheredadjacent the enrobed electrodes to travel or crawl with the direction offlow of the gaseous medium. Thus, when the particles, for instance,leave the influence of electrode 36, they are more or less scooped bythe flange 37a of electrode 37 which assures their becoming subject tothe current between the electrodes 37 and 38. In view of this, it shouldbe readily understandable that the gathering of the particles whichstart with the pollutant removal zone defined by electrodes 34 and 48 iscontrolled and directed in longitudinal movement to effect a virtualconcentration of the foreign material that is carried by the gaseousmedium for ultimate explusion of the same through exit slot 60. In thisregard, a vacuum tube 62 or any other suitable expedient may be used towithdraw the extracted particles from the unit 10.

In energizing the unit 10, high voltage electricity is used with onemeans for accomplishing this purpose being the use of a transformer toincrease the voltage of commercially available electricity. Other meansof producing high voltage electricity, including rectified directcurrent, will, of course, be readily apparent to those skilled in theart. The high voltage is also preferably interrupted or pulsed so as toavoid electrostatic field effects which create back pressure in thedevice 10. For example, a pulsing rate of 6 to 8 pulses per second of avoltage of 15,000 to 20,000 volts should be used for a device 10conveying a flow of 8 cubic feet per second. In any event, when wiringthe unit 10 to receive high voltage electricity, the ground wire 71 willbe led for attachment to the casing 11 as shown at 71a. The output wire72 is led for connection to one or more of the enrobed electrodes as bywires 72a, 72b, 72c, and so on, as is suitable or desired in aparticular installation.

The bare electrodes extend between and are rigidly secured to the bottomwall 16 and the top plate 20 of the casing 11. Consequently, chargingthe casing 11 as described, results in each of the bare electrodesreceiving identical and equal charges. The enrobed electrodes extendthrough apertures in the plates 20 and 22 and are secured in position bymeans of dielectric fasteners 21, 21. To prevent accumulation ofparticles on the electrodes in the space 25 between the plates 20 and 22which might cause a short circuit, nozzle 23 is provided to permit aircirculation in this space.

In use or operation of the improved unit, it will be first assumed thatthe air with pollutant in it enters the upper end of the unit as shownin FIG. 1 and will travel downwardly. The air which passes between thepollutant removal station defined by the bare electrode 35 and theenrobed electrode 36 will deposit micro-particles on the face 36a of theelectrode 36 due to the unbalance created. Pairs of electrodes, such aselectrodes 35 and 36 should be spaced apart at a distance dependent uponthe voltage used. For example, at 15,000 to 20,000 volts, the spacingshould be one-half to five eighths inches. A similar buildup, of course,occurs on electrode 46. As the microparticles agglomerate in size, theywill be more and more influenced by the force of flow in the air andthus will creep down towards the lower end of the unit 36 so as to thenbe ultimately removed therefrom whereupon they will be collected by theend 37a of the electrode 37 co as to be subject to the electrical fieldthat exists between the pollutant removal station of the electrodes 37and 38. A similar progression will occur at the next pollutant removalstation between electrodes 39 and 40 with final collection being in unit60 as has been earlier indicated. It will be noted that in each instancethe width between the flared ends of the outboard electrodes such as 37and 43 is greater than the width between the upstream encapsulatedelectrodes 36 and 46, for example, so that at all times, there is afunneling effect of the ever increasing number of agglomerants so thatthe unit in effect will be progressively cleaned by virtue of the factthat these agglomerants automatically are progressing through the unit.

At the same time, the air passing between electrodes 36 and 46 willremain dirty but a portion of the air stream will be cleaned byelectrodes 37, 38, 43, 44 and the remainder by electrodes 39, 40, 41 sothat the entire stream will have been subject to cleaning by the time itreaches exit slot 60.

It should be noted here that while three groupings of electrodes havebeen illustrated, the invention is not intended to be so limited and thenumber may be varied depending upon the size of the installation.

The modified form of the invention shown in FIGS. 4 and 5 of thedrawings is similar to that previously illustrated in connection withFIGS. 1 through 3, but differs in that insulation is provided withrespect to the metal case so as to improve the overall characteristicsof the unit. Interruption means are further disclosed to causeintermittent interruption to the current for purposes to be described.

Referring now to FIG. 4 of the drawings, all of the bare electrodes andenrobed or encapsulated electrodes are similar in nature to the onesearlier shown in FIG. 1, for example, with the exception that in FIG. 4,two additional bare electrodes 34a and 48a are added to form the mouthopening adjacent the input end. Additionally, the various electrodes34a, 35a, 37, 39, 41, 43, 45 and 48a are suspended with respect to thebend of the unit, as will be noted in FIG. 5 of the drawings, with eachof the units being insulated with respect to the metal by identicalcollars 60, 60 as clearly shown in FIG. 5.

By this arrangement, a harness consisting of branches 71a, 71a jointogether to form a separate outlet wire 71 that replaces the outlet wire71 shown earlier in FIG. ll of the drawings. An interruptor is insertedacross one line 71 or 72 (installed in line 72 in the modification shownin FIG. 4) so as to interrupt the current. It is felt that this currentinterruption is important in that it causes a periodic deposition ofparticles on the electrode surfaces, with the interruption serving toassist the crawling" nature of these particles toward the ultimatecollection point indicated by the numeral 62 in FIG. 4.

It should also be noted that either direct or alternatingacurrent can beused to operate the device.

hlle a full and complete disclosure of the invention has been set forthin accordance with the dictates of the Patent Statutes, it is to beunderstood that modifications may be resorted to without departing fromthe spirit hereof or the scope of the appended claims.

What is claimed is:

1. An electrical pollutant concentrator of the character describedcomprising;

A. a housing having a through passageway that interconnects an input endand an output end;

B. first means for forcing air into said input end through said passage,and out of said output end;

C. a series of pollutant removal zones disposed transversely of saidpassage in the path of air flowing through said passage;

D. each pollutant removal zone including two pollutant removal stations;

E. each pollutant removal station including a bareelectrode and aencapsulated electrode;

F. the transversely spacing between the electrodes of each pollutantremoving station being substantially identical and being relativelysmall in comparison to the overall transverse width of said passageway;

G. second means for creating an electrical field u'nbalance between saidelectrodes of each said station whereby said pollutants will beagglomerated on one such electrode at each such station;

II. the transverse spacing between stations decreasing in each zone;

I. third means for concentrating the pollutants so agglomerated adjacentsaid output end whereby said electrical pollutant concentrator issubstantially self-cleaning.

2. The concentrator of claim 1 further characterized by the fact thatsaid second means include a selectively interrupted electrostatic field.

* i 1 l t

1. An electrical pollutant concentrator of the character describedcomprising; A. a housing having a through passageway that interconnectsan input end and an output end; B. first means for forcing air into saidinput end through said passage, and out of said output end; C. a seriesof pollutant removal zones disposed transversely of said passage in thepath of air flowing through said passage; D. each pollutant removal zoneincluding two pollutant removal stations; E. each pollutant removalstation including a bare electrode and a encapsulated electrode; F. thetransversely spacing between the electrodes of each pollutant removingstation being substantially identical and being relatively small incomparison to the overall transverse width of said passageway; G. secondmeans for creating an electrical field unbalance between said electrodesof each said station whereby said pollutants will be agglomerated on onesuch electrode at each such station; H. the transverse spacing betweenstations decreasing in each zone; I. third means for concentrating thepollutants so agglomerated adjacent said output end whereby saidelectrical pollutant concentrator is substantially self-cleaning.
 2. Theconcentrator of claim 1 further characterized by the fact that saidsecond means include a selectively interrupted electrostatic field.